Residential Building Inspector B1Building Planning and Life SafetyMedium
An inspector is performing a final inspection of a newly constructed single-family dwelling. The dwelling includes a permanently installed clothes washer. What is the minimum required diameter for the standpipe serving the clothes washer discharge?
- A1 1/2 inches
- B3 inches
- C2 inches
- D1 1/4 inches
Show answer & explanationAnswer & explanation
Correct answer: C. 2 inches
According to IRC P2706.3 for clothes washer standpipes, the standpipe shall be not less than 2 inches (51 mm) in diameter. This ensures adequate drainage capacity for the discharge from the washing machine.
Why the other options are wrong
- A. This diameter is too small for a clothes washer standpipe.
- B. This diameter would be sufficient but is not the minimum required.
- D. This diameter is too small for a clothes washer standpipe.
Clothes Washer Standpipe Diameter
Minimum diameter for the plumbing standpipe that receives discharge water from a clothes washing machine.
- Ensures proper drainage.
- Prevents overflow.
- A key plumbing requirement.
Memory trick: For a washer's drain, make sure it's 2 inches wide, or water will rush out with no place to hide.